I was at a class on free motion quilting and it was suggested to use silk thread. It is so much finer than any others it would not show as much if your quilting was not perfect. It would be very expensive. Red Rock threads online sells “InvisaFil” thread. Buy it online. It is 100 weight thread. I’m going to get a panel for a baby quilt and practice going around all the characters then quilting the rest. I have used this thread for stitch in the ditch and liked it fine